WOMEN could help protect themselves against breast cancer by boosting their intake of vitamin D, say researchers.

An active form of the vitamin, calcitriol, is known to be a potent anti-cancer agent.

But British women may not be getting sufficient, because the best source of vitamin D is exposure to sunlight, which is often in short supply in the UK.

Plentiful sunshine could be one reason why breast cancer rates are lower in sunny climates.

Previously, it was thought that calcitriol was only made in the kidney.

But the new research shows that breast tissue contains the enzyme that activates vitamin D and generates calcitriol. Levels of the enzyme are also increased in breast tumours, providing a natural defence against cancer.